A Novel Prediction Technique for Interfacial Crack Growth of Electronic Interconnect
The predicted fatigue life of packaging structures using conventional procedures of finite element analysis (FEA) would be higher than an actual condition as a result of the perfect bonding interface assumed in the modeling. Actually, the crack extension of the solder joints along with the bi-material interface during the thermal cycling test had been observed. And, the crack models with an assumed crack length had widely adopted which only responded to the stress distribution at that moment instead of considering the effect of the whole stress history on the crack advancement. For this reason, a node tie-release crack prediction technique integrated with a nonlinear FEA was established in this research to further estimation for the thermo-mechanical reliability of solder joints. To proof our proposed technique, a double-layer wafer level chip-scaling package (DLWLCSP) was implemented as a testing vehicle to demonstrate the difference between the solder joint reliability, which was compared to the application of conventional FEA. Combined with the fracture criterion, the predicted result of using the present technique shown a lower fatigue life of solder joints than another, which using conventional one when the phenomenon of crack growth in dummy solder joints were considered. Finally, the actual experimental test showed the similar results as presented tie-release crack prediction analysis.
Soon-Bok Lee and Yun-Jae Kim
C. C. Lee et al., "A Novel Prediction Technique for Interfacial Crack Growth of Electronic Interconnect", Key Engineering Materials, Vols. 326-328, pp. 533-536, 2006